Polylactic acid resin composition and resin molded article thereof

ABSTRACT

Provided are a polylactic acid resin composition excellent in transparency, heat resistance, and migration resistance, and excellent in productivity at the time of the mold forming thereof, and a resin molded article thereof. The polylactic acid resin composition includes a polylactic acid; a reaction product of at least one selected from the group consisting of sorbitol, mannitol, and dehydration condensates thereof, an alkylene oxide mainly formed of ethylene oxide, and a fatty acid having 8 to 24 carbon atoms; and a fatty acid amide having a hydroxyl group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. application Ser. No.13/711,595 filed on Dec. 11, 2012, U.S. Provisional Application No.61/570,515 filed on Dec. 14, 2011, and Japanese Application Nos.JP2011-271593 filed on Dec. 12, 2011 and JP2012-183998 filed on Aug. 23,2012 the complete disclosures of which, in their entireties, are herebyincorporated by reference.

BACKGROUND

1. Technical Field

The embodiments herein relate to a polylactic acid resin composition anda resin molded article thereof.

2. Description of the Related Art

While depletion of petroleum resources, a CO₂ reduction, and the likehave been perceived as problems, a polylactic acid using lactic acidobtained by fermenting a grain resource such as corn as a raw materialhas been attracting attention. Polylactic acid is a resin derived from aplant as described above and has the following characteristics:Polylactic acid has high rigidity, and is excellent in transparency.However, its applications have been limited as compared to an ordinaryresin because of, for example, the following reasons: Polylactic acidgenerally has low heat resistance and low impact resistance, and hencetypically cannot be used under a high-temperature condition.

Available as a method of improving the heat resistance of the polylacticacid is, for example, a method involving increasing its crystallinitythrough a heat treatment (annealing treatment). However, the methodinvolves, for example, the following problems. The method is notpractical owing to an extremely long heat treatment time andtransparency of the polylactic acid reduces in association with progressof its crystallization.

In view of the foregoing, blending of various plasticizers and crystalnucleating agents into a resin composition using the polylactic acid asa polymer has been investigated as a method of solving those problems inrecent years.

For example, the following has been proposed as an example of theblending (International Publication No. WO2008/010318A). A fatty acidester formed of a dehydration condensate of a sugar alcohol and a fattyacid is used as the plasticizer, and a layered silicate is used as thecrystal nucleating agent.

In addition to the foregoing, for example, the following has beenproposed (Japanese Patent Application Laid-open No. JP-A-2007-130895). Asaturated ester is used as the plasticizer and an aliphatic ester or afatty acid amide is used as the crystal nucleating agent.

However, generally the applications where the resin compositiondisclosed in WO2008/010318A can be used are extremely limited owing toits low transparency and low heat resistance. Moreover, the resincomposition involves a problem in that productivity at the time of itsmold forming is poor because a molded article thereof is liable todeform upon its removal from the mold unless a molding time during themold forming is set to be long.

On the other hand, the transparency of the resin composition disclosedin JP-A-2007-130895 has been somewhat improved. However, a moldedarticle excellent in transparency and migration resistance typicallycannot be obtained from the resin composition because the resincomposition is liable to be migrated in water or an alcohol. Further,the resin composition still has room for improvement because itsproductivity at the time of the mold forming thereof is not sufficient.

Accordingly, it would be desirable to provide a polylactic acid resincomposition excellent in transparency, heat resistance, and migrationresistance, and excellent in productivity at the time of the moldforming thereof, and a resin molded article thereof.

SUMMARY

In view of the foregoing, an embodiment herein provides a polylacticacid resin composition, including the following components: (A) apolylactic acid; (B) a reaction product of at least one selected fromthe group consisting of sorbitol, mannitol, and dehydration condensatesthereof, and an alkylene oxide mainly formed of ethylene oxide, and afatty acid having 8 to 24 carbon atoms; and (C) a fatty acid amidehaving a hydroxyl group.

Another embodiment provides a resin molded article formed of thepolylactic acid resin composition described above.

The inventors of the present invention have made extensive studies toobtain a polylactic acid resin composition excellent in transparency,heat resistance, and migration resistance, and excellent in productivityat the time of the mold forming thereof. As a result, the inventors ofthe present invention have found that a polylactic acid resincomposition excellent in transparency, heat resistance, and migrationresistance, and excellent in productivity at the time of the moldforming thereof, and a resin molded article thereof can be achieved, andin particular, the transparency is extremely enhanced by the followingprocedure. A specific reaction product, i.e., the reaction product(component B) of at least one selected from the group consisting ofsorbitol, mannitol, and the dehydration condensates thereof, thealkylene oxide mainly formed of ethylene oxide, and the fatty acidhaving 8 to 24 carbon atoms is blended as a plasticizer into a resincomposition using a polylactic acid as a polymer, and the fatty acidamide (component C) having a hydroxyl group is further blended as acrystal nucleating agent into the composition.

As described above, the polylactic acid resin composition of the presentinvention contains the polylactic acid (component A), the specificreaction product (component B), and the fatty acid amide (component C)having a hydroxyl group. Therefore, the composition is excellent intransparency, heat resistance, and migration resistance, and can exertan excellent effect on its productivity at the time of the mold forming(a resin molded article thereof can be efficiently obtained within ashort time period without the occurrence of the deformation at the timeof its removal from the mold). In particular, the transparency isextremely enhanced, and hence the composition can be utilized inapplications requiring high transparency (such as food packagingcontainers). In addition, the composition exerts the following effect.The composition eliminates the need for countermeasures against hightemperatures at the time of, for example, its transportation because thecomposition is excellent in heat resistance and the like.

In particular, when the reaction product as the component B contains anoxyethylene group in a specific range, the polylactic acid resincomposition of the present invention and the resin molded articlethereof each become additionally excellent in transparency, impactresistance, productivity at the time of molding, and the like.

In addition, when the reaction product as the component B has a hydroxylgroup derived from the alkylene oxide, the polylactic acid resincomposition of the present invention and the resin molded articlethereof each become additionally excellent in transparency,compatibility, and dispersibility.

Further, when the reaction product as the component B has a specificamount of an ester group in a molecule thereof, the polylactic acidresin composition of the present invention and the resin molded articlethereof each become additionally excellent in transparency.

In addition, when the fatty acid amide as the component C is a bisamidecompound obtained by causing a fatty acid having 8 to 24 carbon atomsand having a hydroxyl group, and a compound having two amino groups toreact with each other, the polylactic acid resin composition of thepresent invention and the resin molded article thereof each becomeadditionally excellent in transparency, compatibility, dispersibility,and the like.

In addition, when the content of the reaction product as the component Bfalls within a specific range, the polylactic acid resin composition ofthe present invention and the resin molded article thereof each becomeadditionally excellent in transparency, impact resistance, productivityat the time of molding, and the like.

In addition, when the content of the fatty acid amide as the component Cfalls within a specific range, the polylactic acid resin composition ofthe present invention and the resin molded article thereof each becomeadditionally excellent in transparency and productivity at the time ofmolding.

These and other aspects of the embodiments herein will be betterappreciated and understood when considered in conjunction with thefollowing description and the accompanying drawings. It should beunderstood, however, that the following descriptions, while indicatingpreferred embodiments and numerous specific details thereof, are givenby way of illustration and not of limitation. Many changes andmodifications may be made within the scope of the embodiments hereinwithout departing from the spirit thereof, and the embodiments hereininclude all such modifications.

DETAILED DESCRIPTION

The embodiments herein and the various features and advantageous detailsthereof are explained more fully with reference to the non-limitingembodiments that are illustrated in the accompanying drawings anddetailed in the following description. Descriptions of well-knowncomponents and processing techniques are omitted so as to notunnecessarily obscure the embodiments herein. The examples used hereinare intended merely to facilitate an understanding of ways in which theembodiments herein may be practiced and to further enable those of skillin the art to practice the embodiments herein. Accordingly, the examplesshould not be construed as limiting the scope of the embodiments herein.

According to the embodiments herein, the polylactic acid resincomposition contains the polylactic acid (component A), the specificreaction product (component B) (reaction product of at least oneselected from the group consisting of sorbitol, mannitol, and thedehydration condensates thereof, the alkylene oxide mainly formed ofethylene oxide, and the fatty acid having 8 to 24 carbon atoms), and thefatty acid amide (component C) having a hydroxyl group. In thepolylactic acid resin composition of the present invention, the reactionproduct as the component (B) typically has an action as a plasticizerand the fatty acid amide as the component (C) has an action as a crystalnucleating agent. It should be noted that the polylactic acid resincomposition of the present invention can contain, for example, a resinsuch as an acrylic resin, an inorganic filler such as silica, ahydrolysis inhibitor, or an impact modifier in addition to theabove-mentioned components as required.

Polylactic Acid

The polylactic acid (component A) in the polylactic acid resincomposition of the present invention refers to both of a polylactic acidobtained by subjecting only lactic acid as a raw material monomer tocondensation polymerization, and a polylactic acid obtained bysubjecting a lactic acid component and a hydroxycarboxylic acidcomponent except lactic acid (hereinafter, sometimes simply referred toas “hydroxycarboxylic acid component”) as raw material monomers tocondensation polymerization.

Optical isomers, i.e., L-lactic acid (L-form) and D-lactic acid (D-form)exist for lactic acid. Although only one of the optical isomers may, orboth the isomers may each, be incorporated as a lactic acid component inthe present invention, lactic acid having a high optical purity, thelactic acid using one of the optical isomers as a main component, ispreferably used from the viewpoints of: the achievement of compatibilitybetween the flexibility of the polylactic acid resin composition, andits rigidity and heat resistance; and productivity at the time ofmolding. It should be noted that the term “main component” as usedherein refers to a component whose content in the lactic acid componentis 80 mol % or more.

The content of the L-form or the D-form in the lactic acid component,i.e., the content of the more abundant one of the isomers in the casewhere only the lactic acid component is subjected to condensationpolymerization is preferably 95.0 mol % or more, more preferably 98 mol% or more from the above-mentioned viewpoints.

The content of the L-form or the D-form in the lactic acid component,i.e., the content of the more abundant one of the isomers in the casewhere the lactic acid component and the hydroxycarboxylic acid componentare subjected to condensation polymerization is preferably 95.0 mol % ormore, more preferably 98 mol % or more from the above-mentionedviewpoints.

In addition to a product obtained by subjecting only the D-form aslactic acid to condensation polymerization, a product obtained bysubjecting only the L-form as lactic acid to condensationpolymerization, and a product obtained by copolymerizing the D-form andthe L-form, a product obtained by blending a polylactic acid using theL-from as a main component and a polylactic acid using the D-form as amain component at arbitrary ratios may also be used as the polylacticacid.

On the other hand, examples of the hydroxycarboxylic acid componentexcept lactic acid include hydroxycarboxylic acid compounds such asglycolic acid, hydroxybutyric acid, hydroxyvaleric acid,hydroxypentanoic acid, hydroxycaproic acid, and hydroxyheptanoic acid.One kind of those hydroxycarboxylic acid components is used alone, ortwo or more kinds thereof are used in combination. Of those, glycolicacid and hydroxycaproic acid are preferred.

In addition, in the present invention, dimers of lactic acid and thehydroxycarboxylic acid compound may be incorporated into each component.For example, a lactide as a cyclic dimer of lactic acid is used as thedimer of lactic acid, and for example, glycolide as a cyclic dimer ofglycolic acid is used as the dimer of the hydroxycarboxylic acidcompound. It should be noted that the lactides are classified into anL-lactide as a cyclic dimer of L-lactic acid, a D-lactide as a cyclicdimer of D-lactic acid, a meso-lactide obtained by the cyclicdimerization of D-lactic acid and L-lactic acid, and a DL-lactide as aracemic mixture of the D-lactide and the L-lactide. Although each of thelactides can be used in the present invention, the D-lactide and theL-lactide are preferred from the viewpoints of the flexibility andrigidity of the polylactic acid resin composition, and productivity atthe time of the molding of the polylactic acid resin. It should be notedthat the dimer of lactic acid may be incorporated into the lactic acidcomponent in each of the case where only the lactic acid component issubjected to condensation polymerization, and the case where the lacticacid component and the hydroxycarboxylic acid component are subjected tocondensation polymerization.

The condensation polymerization reaction of only the lactic acidcomponent and the condensation polymerization reaction of the lacticacid component and the hydroxycarboxylic acid component are notparticularly limited, and can each be performed by employing a knownmethod.

In addition, the weight-average molecular weight of the polylactic acidin the present invention falls within the range of typically 10,000 to400,000, preferably 50,000 to 400,000. The weight-average molecularweight more preferably falls within the range of 100,000 to 300,000.That is because of the following reasons. When the weight-averagemolecular weight of the polylactic acid falls short of the range, themechanical properties of a resin molded article are low. In contrast,when the weight-average molecular weight of the polylactic acidoutstrips the range, the polylactic acid becomes poor in flowability atthe time of the molding thereof. It should be noted that theweight-average molecular weight of the polylactic acid can be determinedin terms of styrene having a known molecular weight as a reference byusing a gel permeation chromatograph (GPC), chloroform as a solvent, ahigh-temperature SEC column (GMHHR-H series) manufactured by TOSOHCORPORATION as a column with its flow rate and column temperature set to1.0 mL/min and 40° C., respectively, and a refractive index detector(RI) as a detector.

Plasticizer

The reaction product (component B) of at least one selected from thegroup consisting of sorbitol, mannitol, and the dehydration condensatesthereof, the alkylene oxide mainly formed of ethylene oxide, and thefatty acid having 8 to 24 carbon atoms is used as the plasticizer in thepolylactic acid resin composition of the present invention. Examples ofthe dehydration condensate include sorbitan, isosorbide, mannitan, andisomannide. In addition, the term “alkylene oxide mainly formed ofethylene oxide” indicates that ethylene oxide accounts for over half ofthe alkylene oxide and is intended to encompass an alkylene oxideentirely formed of ethylene oxide. It should be noted that, when analkylene oxide except ethylene oxide is used in combination withethylene oxide as the alkylene oxides, for example, propylene oxide,butylene oxide, or isobutylene oxide is used in combination.

A method of producing the reaction product (component B) is, forexample, a method involving: causing sorbitol and the fatty acid toreact with each other under heating to esterify the sorbitol; andsubjecting ethylene oxide to an addition reaction with the resultantunder heating in an autoclave to provide the reaction product (componentB). Alternatively, after sorbitan obtained by subjecting sorbitol todehydration condensation and the fatty acid have been caused to reactwith each other so that the sorbitol may be esterified, ethylene oxidemay be added to the resultant in the same manner as in theabove-mentioned method. Alternatively, after ethylene oxide has beenadded to sorbitan, the fatty acid may be caused to react with theresultant. Alternatively, after a fatty acid ester has been synthesizedfrom the fatty acid and a monohydric alcohol having a small number ofcarbon atoms (methanol or ethanol) in advance, followed by an esterexchange reaction of the ester with sorbitol and sorbitan, ethyleneoxide may be added to the resultant in the same manner as in theabove-mentioned method. Also available is, for example, a methodinvolving: synthesizing a fatty acid ester from the fatty acid and amonohydric alcohol having a small number of carbon atoms (methanol orethanol) in advance; and subjecting the ester to an ester exchangereaction with ethylene oxide adducts of sorbitol and sorbitan to providethe reaction product (component B). In the polylactic acid resincomposition of the present invention, one kind of the reaction products(components B) thus obtained is used alone, or two or more kinds thereofare used in combination.

In addition, the content of an oxyethylene group in the reaction product(component B) is preferably 30 to 95 wt %, more preferably 40 to 95 wt%, even more preferably 50 to 95 wt % from such a viewpoint that thepolylactic acid resin composition of the present invention is excellentin transparency, impact resistance, productivity at the time of molding,and the like.

In addition, the reaction product (component B) preferably has ahydroxyl group derived from the alkylene oxide from such a viewpointthat the polylactic acid resin composition of the present invention isexcellent in transparency, compatibility, and dispersibility. The phrase“having a hydroxyl group derived from the alkylene oxide” as used hereinmeans a state where hydroxyl groups on the side of the alkylene oxidepartially remain without undergoing any esterification with the fattyacid. Such reaction product can be obtained by, for example, subjectingall the hydroxyl groups sorbitol or mannitol, or a dehydrationcondensate thereof has to an addition reaction with the alkylene oxide,and subjecting only part of the terminal hydroxyl groups on the side ofthe alkylene oxide after the addition reaction to an esterificationreaction with the fatty acid.

In addition, the reaction product (component B) has preferably 0.5 ormore and less than 2.5, more preferably 0.5 or more and 2.0 or lessester groups on average in a molecule thereof from the viewpoint of thetransparency.

Further, the fatty acid having 8 to 24 carbon atoms is used in thesynthesis of the reaction product (component B) and a fatty acid having10 to 24, more preferably 12 to 24 carbon atoms is preferably used fromsuch a viewpoint that the polylactic acid resin composition of thepresent invention is excellent in transparency, impact resistance, andin migration resistance for water and an alcohol-based solvent. That isbecause of the following reasons: when the number of carbon atoms in thefatty acid falls short of the range, desired impact resistance is hardlyobtained. Further, the amount of the composition to be migrated in wateror the alcohol-based solvent increases. In contrast, when the number ofcarbon atoms in the fatty acid outstrips the range, the composition hasbad compatibility with the polylactic acid (A) as a polymer and is poorin transparency. It should be noted that a fatty acid corresponding toany one of a saturated fatty acid and an unsaturated fatty acid may beused as the fatty acid, and the fatty acids may be used in combination.Alternatively, the fatty acid may be a mixture of fatty acidstransformed from oils and fats. In that case, a mixture whose averagenumber of carbon atoms falls within the range is used.

In addition, specific examples of the reaction product (component B)include a polyoxyethylene sorbitol caprylate, a polyoxyethylene sorbitolcaprate, a polyoxyethylene sorbitol laurate, a polyoxyethylene sorbitolcocoate, a polyoxyethylene sorbitol myristate, a polyoxyethylenesorbitol palmitate, a polyoxyethylene sorbitol linoleate, apolyoxyethylene sorbitol stearate, a polyoxyethylene sorbitolisostearate, a polyoxyethylene sorbitol-12-hydroxystearate, apolyoxyethylene sorbitol oleate, a polyoxyethylene sorbitol eicosanoate,a polyoxyethylene sorbitol behenate, a polyoxyethylene sorbitollignocerate, a polyoxyethylene sorbitan caprylate, a polyoxyethylenesorbitan caprate, a polyoxyethylene sorbitan laurate, a polyoxyethylenesorbitan cocoate, a polyoxyethylene sorbitan myristate, apolyoxyethylene sorbitan palmitate, a polyoxyethylene sorbitanlinoleate, a polyoxyethylene sorbitan stearate, a polyoxyethylenesorbitan isostearate, a polyoxyethylene sorbitan-12-hydroxystearate, apolyoxyethylene sorbitan oleate, a polyoxyethylene sorbitan eicosanoate,a polyoxyethylene sorbitan behenate, a polyoxyethylene sorbitanlignocerate, a polyoxyethylene isosorbide caprylate, a polyoxyethyleneisosorbide caprate, a polyoxyethylene isosorbide laurate, apolyoxyethylene isosorbide cocoate, a polyoxyethylene isosorbidemyristate, a polyoxyethylene isosorbide palmitate, a polyoxyethyleneisosorbide linoleate, a polyoxyethylene isosorbide stearate, apolyoxyethylene isosorbide isostearate, a polyoxyethyleneisosorbide-12-hydroxystearate, a polyoxyethylene isosorbide oleate, apolyoxyethylene isosorbide eicosanoate, a polyoxyethylene isosorbidebehenate, a polyoxyethylene isosorbide lignocerate, a polyoxyethylenemannitol caprylate, a polyoxyethylene mannitol caprate, apolyoxyethylene mannitol laurate, a polyoxyethylene mannitol cocoate, apolyoxyethylene mannitol myristate, a polyoxyethylene mannitolpalmitate, a polyoxyethylene mannitol linoleate, a polyoxyethylenemannitol stearate, a polyoxyethylene mannitol isostearate, apolyoxyethylene mannitol-12-hydroxystearate, a polyoxyethylene mannitololeate, a polyoxyethylene mannitol eicosanoate, a polyoxyethylenemannitol behenate, a polyoxyethylene mannitol lignocerate, apolyoxyethylene mannitan caprylate, a polyoxyethylene mannitan caprate,a polyoxyethylene mannitan laurate, a polyoxyethylene mannitan cocoate,a polyoxyethylene mannitan myristate, a polyoxyethylene mannitanpalmitate, a polyoxyethylene mannitan linoleate, a polyoxyethylenemannitan stearate, a polyoxyethylene mannitan isostearate, apolyoxyethylene mannitan-12-hydroxystearate, a polyoxyethylene mannitanoleate, a polyoxyethylene mannitan eicosanoate, a polyoxyethylenemannitan behenate, a polyoxyethylene mannitan lignocerate, apolyoxyethylene isomannide caprylate, a polyoxyethylene isomannidecaprate, a polyoxyethylene isomannide laurate, a polyoxyethyleneisomannide cocoate, a polyoxyethylene isomannide myristate, apolyoxyethylene isomannide palmitate, a polyoxyethylene isomannidelinoleate, a polyoxyethylene isomannide stearate, a polyoxyethyleneisomannide isostearate, a polyoxyethylene isomannide-12-hydroxystearate,a polyoxyethylene isomannide oleate, a polyoxyethylene isomannideeicosanoate, a polyoxyethylene isomannide behenate, and apolyoxyethylene isomannide lignocerate. One kind of those reactionproducts is used alone, or two or more kinds thereof are used incombination. It should be noted that as one or a plurality of fatty acidester groups exist in one molecule of each of the reaction productslisted above, the term “polyoxyethylene sorbitol caprylate,” forexample, is intended to encompass “polyoxyethylene sorbitolmonocaprylate, polyoxyethylene sorbitol sesquicaprylate, polyoxyethylenesorbitol dicaprylate, and the like.”

The content of the reaction product (component B) in the polylactic acidresin composition of the present invention falls within the range ofpreferably 0.5 to 10 parts by weight, more preferably 1 to 10 parts byweight, even more preferably 2 to 10 parts by weight, most preferably 3to 10 parts by weight with respect to 100 parts by weight of thepolylactic acid (component A) from such a viewpoint that the compositionbecomes excellent in transparency, impact resistance, productivity atthe time of the molding thereof, and the like.

Crystal Nucleating Agent

The fatty acid amide (component C) having a hydroxyl group is used asthe crystal nucleating agent in the polylactic acid resin composition ofthe present invention from the viewpoints of, for example, themoldability, heat resistance, impact resistance, and transparency of apolylactic acid resin molded article.

In addition, the fatty acid amide (component C) is preferably a bisamidecompound obtained by causing a fatty acid having 8 to 24 carbon atomsand having a hydroxyl group, and a compound having two amino groups toreact with each other because the polylactic acid resin composition ofthe present invention becomes excellent in transparency, compatibility,dispersibility, and the like. It should be noted that a fatty acidcorresponding to any one of a saturated fatty acid and an unsaturatedfatty acid may be used as the fatty acid, and the fatty acids may beused in combination. Alternatively, the fatty acid may be a mixture offatty acids transformed from oils and fats. In that case, a mixturewhose average number of carbon atoms falls within the range is used.

In addition, specific examples of the fatty acid amide (component C)include N,N′-ethylenebis-8-hydroxycapric acid amide,N,N′-butylenebis-8-hydroxycapric acid amide,N,N′-hexamethylenebis-8-hydroxycapric acid amide,N,N′-m-xylylenebis-8-hydroxycapric acid amide,N,N′-ethylenebis-12-hydroxylauric acid amide,N,N′-butylenebis-10-hydroxylauric acid amide,N,N′-hexamethylenebis-10-hydroxylauric acid amide,N,N′-m-xylylenebis-10-hydroxylauric acid amide,N,N′-ethylenebis-11-hydroxymyristic acid amide,N,N′-butylenebis-11-hydroxymyristic acid amide,N,N′-hexamethylenebis-11-hydroxymyristic acid amide,N,N′-m-xylylenebis-11-hydroxymyristic acid amide,N,N′-ethylenebis-16-hydroxypalmitic acid amide,N,N′-butylenebis-16-hydroxypalmitic acid amide,N,N′-hexamethylenebis-16-hydroxypalmitic acid amide,N,N′-m-xylylenebis-16-hydroxypalmitic acid amide,N,N′-ethylenebis-12-hydroxystearic acid amide,N,N′-butylenebis-12-hydroxystearic acid amide,N,N′-hexamethylenebis-12-hydroxystearic acid amide,N,N′-m-xylylenebis-12-hydroxystearic acid amide,N,N′-butylenebis-2-hydroxyarachidic acid amide,N,N′-hexamethylenebis-2-hydroxyarachidic acid amide,N,N′-m-xylylenebis-2-hydroxyarachidic acid amide,N,N′-ethylenebis-2-hydroxybehenic acid amide,N,N′-butylenebis-2-hydroxybehenic acid amide,N,N′-hexamethylenebis-2-hydroxybehenic acid amide,N,N′-m-xylylenebis-2-hydroxybehenic acid amide,N,N′-ethylenebis-2-hydroxylignoceric acid amide,N,N′-butylenebis-2-hydroxylignoceric acid amide,N,N′-hexamethylenebis-2-hydroxylignoceric acid amide,N,N′-m-xylylenebis-2-hydroxylignoceric acid amide,N,N′-ethylenebis-12-hydroxyoleic acid amide,N,N′-butylenebis-12-hydroxyoleic acid amide,N,N′-hexamethylenebis-12-hydroxyoleic acid amide,N,N′-m-xylylenebis-12-hydroxyoleic acid amide,N,N′-ethylenebis-11-hydroxylinoleic acid amide,N,N′-butylenebis-11-hydroxylinoleic acid amide,N,N′-hexamethylenebis-11-hydroxylinoleic acid amide,N,N′-m-xylylenebis-11-hydroxylinoleic acid amide,N,N′-ethylenebis-11-hydroxyarachidonic acid amide,N,N′-butylenebis-11-hydroxyarachidonic acid amide,N,N′-hexamethylenebis-11-hydroxyarachidonic acid amide, andN,N′-m-xylylenebis-11-hydroxyarachidonic acid amide. One kind of thosefatty acid amides is used alone, or two or more kinds thereof are usedin combination.

The content of the fatty acid amide (component C) in the polylactic acidresin composition of the present invention falls within the range ofpreferably 0.1 to 0.7 part by weight with respect to 100 parts by weightof the polylactic acid (component A) from such a viewpoint that thecomposition becomes excellent in transparency and productivity at thetime of the molding.

Other Resin

In addition to the components (A) to (C), any other resin may beappropriately incorporated into the polylactic acid resin composition ofthe present invention as long as an effect of the present invention isnot impaired (i.e., in the range of less than 20 wt %, preferably 1 to15 wt %, more preferably 1 to 10 wt % of the whole polylactic acid resincomposition). Examples of the other resin include: thermoplastic resinssuch as an acrylic resin, a polypropylene, a polystyrene, an ABS resin,an AS resin, a polyphenylene sulfide, a polyetheretherketone, apolyester, a polyacetal, a polysulfone, a polyphenylene oxide, and apolyetherimide; and thermosetting resins such as a phenol resin, amelamine resin, an unsaturated polyester resin, a silicone resin, and anepoxy resin. One kind of those resins is used alone, or two or morekinds thereof are used in combination. Of those, an acrylic resin ispreferred from the viewpoints of excellence in impact resistance and thelike, and a smaller influence on the transparency.

Inorganic Filler

Further, an inorganic filler may be incorporated into the polylacticacid resin composition of the present invention as required. Specificexamples of the inorganic filler include silica, surface-treated silicatreated with a silane coupling agent or the like, talc, clay, mica,zeolite, bentonite, montmorillonite, a glass fiber, and a carbon fiber.One kind of those inorganic fillers is used alone, or two or more kindsthereof are used in combination. Of those, silica (includingsurface-treated silica) is preferred from such a viewpoint that thecomposition becomes excellent in impact resistance and bending strength.

In addition, the content of the inorganic filler in the polylactic acidresin composition of the present invention falls within the range ofpreferably 0.01 to 2 parts by weight, more preferably 0.01 to 1 part byweight with respect to 100 parts by weight of the polylactic acid(component A) from such a viewpoint that the composition becomesexcellent in impact resistance, bending strength, and the like.

Hydrolysis Inhibitor

In addition, a hydrolysis inhibitor may be incorporated into thepolylactic acid resin composition of the present invention as required.Examples of the hydrolysis inhibitor include carbodiimide compounds suchas a polycarbodiimide compound and a monocarbodiimide compound. Ofthose, a polycarbodiimide compound is preferred from the viewpoint ofthe moldability of the polylactic acid resin molded article, and amonocarbodiimide compound is more preferred from the viewpoints of theheat resistance, moldability, flowability, and impact resistance of thepolylactic acid resin molded article, and the blooming resistance of thecrystal nucleating agent.

Examples of the polycarbodiimide compound include apoly(4,4′-diphenylmethanecarbodiimide), apoly(4,4′-dicyclohexylmethanecarbodiimide), apoly(1,3,5-triisopropylbenzene)polycarbodiimide, and apoly(1,3,5-triisopropylbenzene and1,5-diisopropylbenzene)polycarbodiimide. The monocarbodiimide compoundis, for example, N,N′-di-2,6-diisopropylphenylcarbodiimide.

In addition, the content of the hydrolysis inhibitor in the polylacticacid resin composition of the present invention falls within the rangeof preferably 0.05 to 2 parts by weight, more preferably 0.1 to 1 partby weight with respect to 100 parts by weight of the polylactic acid(component A) from the viewpoint of the moldability of the polylacticacid resin molded article.

Impact Modifier

In addition, an impact modifier may be incorporated into the polylacticacid resin composition of the present invention as required from theviewpoints of improvements in its physical properties such asflexibility. A (meth)acrylic acid polymer, an ethylene-(meth)acrylicacid copolymer, an ethylene-alkyl (meth)acrylate copolymer, anepoxy-modified silicone acrylic rubber, a copolymer of a diene and avinyl monomer, and a hydrogenated product thereof, organic fibers suchas an aromatic polyamide fiber, a diene rubber, a compatibilizer, andthe like can each be used as the impact modifier. It should be notedthat the term “(meth)acrylic acid” refers to acrylic acid and/ormethacrylic acid.

In addition, the content of the impact modifier in the polylactic acidresin composition of the present invention falls within the range ofpreferably 1 to 20 parts by weight, more preferably 3 to 10 parts byweight with respect to 100 parts by weight of the polylactic acid(component A) from the viewpoints of the impact resistance andmoldability of the resin composition.

The polylactic acid resin composition of the present invention cancontain a flame retardant, an antioxidant, a lubricant, an antistaticagent, an anti-fogging agent, a light stabilizer, a UV absorber, apigment, a colorant, an antifungal agent, an antibacterial agent, afoaming agent, or the like as any other component except the foregoingto such an extent that the achievement of the object of the presentinvention is not impaired.

Production of Polylactic Acid Resin Composition and Resin Molded ArticleThereof

The polylactic acid resin composition of the present invention can beprepared by: blending the polylactic acid (component A), the specificreaction product (component B) as a plasticizer, and the fatty acidamide (component C) as a crystal nucleating agent, and as required, anyother material at predetermined ratios; and melting and mixing thematerials at 160 to 240° C. It should be noted that the melting andmixing may be performed after the respective materials have beenblended. Alternatively, the composition may be prepared by the followingprocedure. After the polylactic acid (component A) has been previouslymelted with an extruder, a Banbury mixer, a kneader, a heating roll, orthe like, the other materials are blended into the molten product andthen the mixture is shaped into a uniform pellet shape.

Then, a resin molded article can be obtained by using the resincomposition melted and mixed as described above as a material throughcast molding, injection molding, blow molding, extrusion molding, or thelike. In addition, the composition can be molded into various moldedarticles by molding methods such as vacuum molding, pressure molding,and vacuum pressure molding after the composition has been processedinto a sheet.

When the composition is formed with a mold for obtaining the resinmolded article, the temperature of the mold at the time of the moldingfalls within the range of preferably 40 to 140° C., more preferably 70to 120° C. from the viewpoint of productivity. In addition, the timeperiod for which the resin molded article is held in the mold in vacuummolding, pressure molding, or vacuum pressure molding is preferably 1 to15 seconds, more preferably 1 to 10 seconds from the viewpoints ofproductivity and the like.

It should be noted that the thickness of a molded article using thepolylactic acid resin composition of the present invention as a materialis typically about 0.1 to 0.5 mm. However, for example, when thecomposition is molded into a molded article having a thickness of 0.4 mmand its cloudiness (haze) is measured with a HAZE meter (trade name:Haze Computer HZ-2, manufactured by Suga Test Instruments, Co., Ltd.),the value can be suppressed to less than 15%, preferably less than 10%.The molded article can be used as a resin molded article having hightransparency because its cloudiness (haze) is small as described above.In addition, the polylactic acid resin composition of the presentinvention shows a small degree of deterioration of its transparency overtime and has high heat resistance, and hence the molded article shows,for example, the following characteristic. Even after the molded articlehas been left to stand under a high temperature around 90° C., nearly nodeterioration of its transparency is observed.

In addition, the migration amount of the polylactic acid resin moldedarticle of the present invention was measured in accordance with anmigration test method specified in the FCN system concerning a foodpackaging container of the U.S. Food and Drug Administration (FDA), andthen its cumulative estimated daily intake (CEDI) was calculated.Smaller values for the migration amount and the CEDI mean that themigration amount from the molded article is smaller (the molded articleis more excellent in migration resistance). The CEDI's of the polylacticacid resin composition of the present invention and the molded articlethereof can each be suppressed to less than 1 ppm, preferably less than0.5 ppm. As described above, their CEDI's are low, and hence the resincomposition and the molded article show low migration amounts at thetime of their use and can be safely used as food packaging containers.In addition, reductions in physical properties of the resin compositionand the molded article are suppressed because their migration amountsare small.

As described above, each of the polylactic acid resin composition of thepresent invention and the resin molded article thereof is excellent intransparency, heat resistance, and the like, and has highbiodegradability. Accordingly, the polylactic acid resin composition ofthe present invention and the resin molded article thereof can besuitably utilized in applications including: various disposablecontainers (e.g., food containers such as a tray for fresh food, aninstant food container, a fast food container, a lunch box, a beveragebottle, and a container for a flavor such as mayonnaise, an agriculturaland horticultural container such as a seedling pot, a blister packcontainer, and a press-through pack container); CD cases; clear filefolders; cards such as a credit card; dinnerware such as a spoon and adrinking straw; plastic models; various resin products such as a resinsheet, a resin film, and a resin hose; and textile goods such as a fiberfor clothing and a nonwoven fabric. Further, the polylactic acid resincomposition of the present invention can be suitably utilized in widerfields than a conventional polylactic acid resin composition is becauseits transparency, heat resistance, and the like have been improved ascompared to those of the conventional polylactic acid resin composition.

EXAMPLES

Next, examples are described together with comparative examples.However, the present invention is not limited to these examples.

First, the following materials were prepared prior to the examples andthe comparative examples.

Polylactic Acid A-1

Polylactic acid (trade name: 4032D, manufactured by Natureworks LLC.)

Plasticizer B-1

Polyoxyethylene sorbitan monococoate (content of oxyethylene group: 72wt %, trade name: SOLGEN TW-20, manufactured by DAI-ICHI KOGYO SEIYAKUCO., LTD.)

Plasticizer B-2

Polyoxyethylene sorbitan monostearate (content of oxyethylene group: 67wt %, trade name: SOLGEN TW-60, manufactured by DAI-ICHI KOGYO SEIYAKUCO., LTD.)

Plasticizer B-3

Polyoxyethylene sorbitan monooleate (content of oxyethylene group: 67 wt%, trade name: SOLGEN TW-80, manufactured by DAI-ICHI KOGYO SEIYAKU CO.,LTD.)

Plasticizer B-4

Polyoxyethylene sorbitan monobehenate (content of oxyethylene group: 64wt %, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-5

Polyoxyethylene mannitan monostearate (content of oxyethylene group:67%, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-6

Polyoxyethylene isosorbide monostearate (content of oxyethylene group:65 wt %, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-7

Polyoxyethylene sorbitan distearate (content of oxyethylene group: 65 wt%, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-8

Polyoxyethylene sorbitan dilaurate (content of oxyethylene group: 71 wt%, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-9

Polyoxyethylene sorbitan dibehenate (content of oxyethylene group: 62 wt%, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-10

Polyoxyethylene sorbitan monostearate (content of oxyethylene group: 51wt %, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-11

Polyoxyethylene sorbitan monostearate (content of oxyethylene group: 86wt %, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-12

Polyoxyethylene sorbitan distearate (content of oxyethylene group: 53 wt%, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-13

Polyoxyethylene sorbitan distearate (content of oxyethylene group: 83 wt%, prepared by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer B-14

Polyoxyethylene sorbitan mono-12-hydroxystearate (content of oxyethylenegroup: 67 wt %.)

Plasticizer B-15

Polyoxyethylene sorbitan sesquistearate (content of oxyethylene group:65 wt %.)

Plasticizer b-1

Sorbitan monostearate (content of oxyethylene group: 0 wt %, trade name:SOLGEN 50V, manufactured by DAI-ICHI KOGYO SEIYAKU CO., LTD.)

Plasticizer b-2

Glycerin monostearate (content of oxyethylene group: 0 wt %, trade name:EXCEL S-95, manufactured by Kao Corporation.)

Plasticizer b-3

Diester formed of succinic acid and triethylene glycol monomethyl ether(content of oxyethylene group: 64 wt %.)

Plasticizer b-4

Fatty acid ester of polyglycerin (content of oxyethylene group: 0 wt %,trade name: CHIRABAZOL VR-05, manufactured by Taiyo Kagaku Co., Ltd.)

Crystal Nucleating Agent C-1

N,N′-Ethylenebis-12-hydroxystearic acid amide (trade name: ITOHWAXJ-530, manufactured by ITOH OIL CHEMICALS CO., LTD.)

Crystal Nucleating Agent C-2

N,N′-Hexamethylenebis-12-hydroxystearic acid amide (trade name: ITOHWAXJ-630, manufactured by ITOH OIL CHEMICALS CO., LTD.)

Crystal Nucleating Agent C-3

N,N′-Xylylenebis-12-hydroxystearic acid amide (trade name: ITOHWAXJ-700, manufactured by ITOH OIL CHEMICALS CO., LTD.)

Crystal Nucleating Agent C-4

N,N′-Ethylenebis-8-hydroxycaprylic acid amide (obtained by theproduction method disclosed in Japanese Patent Application Laid-open No.Sho 63-60956.)

Crystal Nucleating Agent C-5

N,N′-Ethylenebis-2-hydroxybehenic acid amide (obtained by the productionmethod disclosed in Japanese Patent Application Laid-open No. Sho63-60956.)

Crystal Nucleating Agent c-1

Talc (trade name: MICRO ACE P-6, manufactured by Nippon Talc Co.,

Ltd.)

Crystal Nucleating Agent c-2

Stearic acid amide (manufactured by TOKYO CHEMICAL INDUSTRY CO., LTD.)

Crystal Nucleating Agent c-3

Montmorillonite, in which an ion between layers is substituted by adioctadecyldimethylammonium ion (trade name: S-BEN W, manufactured byHOJUN CO., LTD.)

Acrylic Resin D-1

Polymethyl methacrylate (trade name: ACRYPET HV, manufactued byMITSUBISHI RAYON CO., LTD.)

Silica E-1

Silica modified with a poly-D-lactic acid (obtained by Synthesis Example1 below.)

Synthesis Example 1

10.0 Grams of tetraethoxysilane were dissolved in 990 g of D-lactic acid(manufactured by Purac, 90-mass % aqueous solution), and then subjectedto dehydration condensation at 130° C. for 4 hours while the resultantmixture was subjected to nitrogen bubbling. Further, dehydrationpolymerization was performed by stirring the mixture at 170° C. under areduced pressure of 5 mmHg for 12 hours. After that, a fluid polymerobtained by the reaction was taken out and cooled to be solidified.Thus, about 680 g of silica modified with a colorless, transparentpoly-D-lactic acid (silica content: 0.42%) were obtained.

Silica E-2

Fumed silica (trade name: REOLOSIL QS-102, manufactured by TokuyamaCorporation, content of silica: >99.9%.)

Antioxidant F-1

Hindered phenolic antioxidant (trade name: IRGANOX 1076, manufactured byBASF.)

Examples 1 to 31 and Comparative Examples 1 to 10

The respective materials were blended at ratios shown in Table 1 toTable 5 below, and then the mixtures were heated and kneaded with abiaxial extruder (KZW20-30MG manufactured by TECHNOVEL CORPORATION)under the condition of a temperature of its cylinder of 160 to 190° C.Thus, pellets of resin compositions were obtained. It should be notedthat the pellets were dried under reduced pressure at a temperature of70° C. for 12 hours or more.

The polylactic acid resin compositions (pellets) of the examples and thecomparative examples thus obtained were measured and evaluated for theirrespective characteristics in accordance with the following criteria.Table 1 to Table 5 below show the results together.

Mold Holding Time

A sheet having a thickness of 0.4 mm was produced from each of thepellets with a T-die extruder (manufactured by TECHNOVEL CORPORATION).After that, the sheet was heated from above and below with an infraredheater at about 300° C. to be softened. Subsequently, the sheet wasloaded into a mold with its temperature controlled to 90° C., and wasthen subjected to vacuum pressure molding, followed by removal from themold. Thus, a resin molded article was obtained. During the removal fromthe mold, the shortest time required for the resin molded article to betaken out of the mold without any deformation (mold holding time) wasmeasured. It should be noted that productivity becomes higher as theshortest time shortens.

Heat Resistance

The resin molded article (molded article formed of the polylactic acidresin composition) obtained by such mold forming as described above wasloaded into an oven at 90° C. and held for 30 minutes. Then, the moldedarticle was evaluated as ∘ when no deformation was observed after theheating, or was evaluated as x when the molded article deformed afterthe heating.

Initial Transparency

The cloudiness (haze) of the resin molded article (initial stage)obtained by such mold forming as described above was measured with aHAZE meter (trade name: Haze Computer HZ-2, manufactured by Suga TestInstruments, Co., Ltd.). It should be noted that a smaller value (%) forthe haze means that the resin molded article has better transparency.

Time-Varying Transparency

After the resin molded article had been loaded into an oven at 90° C.and held for 24 hours, its cloudiness (haze) was measured with a HAZEmeter (trade name: Haze Computer HZ-2, manufactured by Suga TestInstruments, Co., Ltd.). It should be noted that a smaller value (%) forthe haze means that the resin molded article has better transparency.

CEDI

The migration amount of the resin molded article (molded article formedof the polylactic acid resin composition) obtained by such mold formingas described above was measured in accordance with an migration testmethod specified in the FCN system of the U.S. Food and DrugAdministration (FDA), and then its cumulative estimated daily intake(CEDI) was calculated. It should be noted that in the migration test,10% ethanol was used as a food simulant, and was heated under theconditions of 66° C. and 2 hours. Then, the migration amount wasdetermined by quantifying a substance migrated in the food simulantthrough gas chromatography, followed by the calculation of the CEDI(ppm). It should be noted that a smaller value for the CEDI means thatthe resin molded article is more excellent in migaration resistance.

TABLE 1 Part(s) by weight Example 1 2 3 4 5 6 7 8 9 Polylactic acid A-1100 100 100 100 100 100 100 100 100 Plasticizer B-1 5 — — — — — — — —B-2 — 5 — — — — — — — B-3 — — 5 — — — — — — B-4 — — — 5 — — — — — B-5 —— — — 5 — — — — B-6 — — — — — 5 — — — B-7 — — — — — — 5 — — B-8 — — — —— — — 5 — B-9 — — — — — — — — 5 Crystal nucleating agent C-1 0.4 0.4 0.40.4 0.4 0.4 0.4 0.4 0.4 C-2 — — — — — — — — — C-3 — — — — — — — — — C-4— — — — — — — — — C-5 — — — — — — — — — Acrylic resin D-1 — — — — — — —— — Silica E-1 — — — — — — — — — E-2 — — — — — — — — — Antioxidant F-10.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Mold holding time (s) 5 5 5 5 5 5 55 5 Heat resistance ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ Initial transparency (%) 4.5 4.55.2 5.1 4.5 8.9 5.1 5.1 5.2 Time-varying transparency (%) 4.9 4.9 5.85.8 4.9 10.5 5.3 5.2 6.0 CEDI (ppm) 0.27 0.26 0.26 0.24 0.26 0.26 0.200.20 0.19

TABLE 2 Part(s) by weight Example 10 11 12 13 14 15 16 17 18 Polylacticacid A-1 100 100 100 100 100 100 100 100 100 Plasticizer B-2 — — — — — —5 5 5 B-10 5 — — — — — — — — B-11 — 5 — — — — — — — B-12 — — 5 — — — — —— B-13 — — — 5 — — — — — B-14 — — — — 5 — — — — B-15 — — — — — 5 — — —Crystal nucleating agent C-1 0.4 0.4 0.4 0.4 0.4 0.4 — — — C-2 — — — — —— 0.4 — — C-3 — — — — — — — 0.4 — C-4 — — — — — — — — 0.4 C-5 — — — — —— — — — Acrylic resin D-1 — — — — — — — — — Silica E-1 — — — — — — — — —E-2 — — — — — — — — — Antioxidant F-1 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.30.3 Mold holding time (s) 5 5 5 5 5 5 5 5 5 Heat resistance ∘ ∘ ∘ ∘ ∘ ∘∘ ∘ ∘ Initial transparency (%) 5.5 4.5 5.7 4.9 4.5 4.8 4.7 4.7 5.0Time-varying transparency (%) 5.9 4.8 6.1 5.2 4.9 5.1 5.5 5.3 5.6 CEDI(ppm) 0.27 0.21 0.19 0.20 0.26 0.26 0.26 0.26 0.26

TABLE 3 Part(s) by weight Example 19 20 21 22 23 24 25 26 Polylacticacid A-1 100 100 100 100 100 100 100 100 Plasticizer B-2 5 5 5 3 10 5 55 Crystal nucleating agent C-1 — 0.1 0.7 0.4 0.4 0.4 0.4 0.4 C-2 — — — —— — — — C-3 — — — — — — — — C-4 — — — — — — — — C-5 0.4 — — — — — — —Acrylic resin D-1 — — — — — 5 — — Silica E-1 — — — — — — 10 — E-2 — — —— — — — 0.1 Antioxidant F-1 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Mold holdingtime (s) 5 5 5 5 5 5 5 5 Heat resistance ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ Initialtransparency (%) 4.9 6.4 7.4 5.1 7.5 4.7 4.6 4.7 Time-varyingtransparency (%) 5.4 7.0 8.3 6.1 8.2 5.0 5.0 5.1 CEDI (ppm) 0.26 0.260.26 0.15 0.48 0.25 0.25 0.25

TABLE 4 Part(s) by weight Example 27 28 29 30 31 Polylactic acid A-1 100100 100 100 100 Plasticizer B-2 0.5 1 1 1 1 Crystal nucleating C-1 0.40.4 0.7 0.4 0.4 agent C-2 — — — — — C-3 — — — — — C-4 — — — — — C-5 — —— — — Acrylic resin D-1 — — — 3 5 Silica E-1 — — — — — E-2 — — — — —Antioxidant F-1 0.3 0.3 0.3 0.3 0.3 Mold holding time (s) 5 5 5 5 5 Heatresistance ∘ ∘ ∘ ∘ ∘ Initial transparency (%) 5.4 5.2 5.8 4.9 5.1Time-varying 6.2 6.0 6.4 5.9 6.0 transparency (%) CEDI (ppm) 0.02 0.040.04 0.04 0.04

TABLE 5 Part(s) by weight Comparative Example 1 2 3 4 5 6 7 8 9 10Polylactic acid A-1 100 100 100 100 100 100 100 100 100 100 PlasticizerB-2 — — — — — 5 5 5 5 — b-1 5 — — — — — — — — — b-2 — 5 — — — — — — — —b-3 — — 5 — — — — — — — b-4 — — — 5 — — — — — — Crystal nucleating agentC-1 0.4 0.4 0.4 0.4 0.4 — — — — — C-2 — — — — — — — — — — C-3 — — — — —— — — — — C-4 — — — — — — — — — — C-5 — — — — — — — — — — c-1 — — — — —0.4 — — — — c-2 — — — — — — 0.4 — — — c-3 — — — — — — — 0.4 — — Acrylicresin D-1 — — — — — — — — — — Silica E-1 — — — — — — — — — — E-2 — — — —— — — — — — Antioxidant F-1 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Moldholding time (s) 25 45 20 25 25 45 60 60 60 600 Heat resistance x x ∘ ∘∘ ∘ x x x ∘ Initial transparency (%) 73 67 15 25 26 72 72 72 84 91Time-varying transparency (%) 94 93 40 47 44 86 92 84 94 94 CEDI (ppm)2.84 3.44 3.24 0.25 0.01 0.26 0.26 0.26 0.26 0.01

As can be seen from the results of Table 1 to Table 5, the polylacticacid resin compositions of the examples each had high productivitybecause their mold holding times were shorter than those of thepolylactic acid resin compositions of the comparative examples. Further,the polylactic acid resin compositions of the examples were eachexcellent in heat resistance because none of the resin molded articlesthereof showed deformation due to heating. In addition, the polylacticacid resin compositions of the examples each had small values for thecloudiness (haze) of the resin molded article at the initial stage andafter the heat resistance test and were each excellent in transparencyand migration resistance as compared to the polylactic acid resincompositions of the comparative examples.

The polylactic acid resin composition of the present invention and theresin molded article thereof can be suitably utilized in applicationsincluding: various disposable containers (e.g., food containers such asa tray for fresh food, an instant food container, a fast food container,a lunch box, a beverage bottle, and a container for a flavor such asmayonnaise, an agricultural and horticultural container such as aseedling pot, a blister pack container, and a press-through packcontainer); CD cases; clear file folders; cards such as a credit card;dinnerware such as a spoon and a drinking straw; plastic models; variousresin products such as a resin sheet, a resin film, and a resin hose;and textile goods such as a fiber for clothing and a nonwoven fabric.Further, the polylactic acid resin composition of the present inventioncan be suitably utilized in wider fields than a conventional polylacticacid resin composition is because its transparency, heat resistance,migration resistance, and the like have been improved as compared tothose of the conventional polylactic acid resin composition.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the embodiments herein that others can, byapplying current knowledge, readily modify and/or adapt for variousapplications such specific embodiments without departing from thegeneric concept, and, therefore, such adaptations and modificationsshould and are intended to be comprehended within the meaning and rangeof equivalents of the disclosed embodiments. It is to be understood thatthe phraseology or terminology employed herein is for the purpose ofdescription and not of limitation. Therefore, while the embodimentsherein have been described in terms of preferred embodiments, thoseskilled in the art will recognize that the embodiments herein can bepracticed with modification within the spirit and scope of the appendedclaims.

1. A polylactic acid resin composition consisting essentially of: (i) apolylactic acid; (ii) a reaction product of: at least one selected fromthe group consisting of sorbitol, mannitol, and dehydration condensatesthereof, an alkylene oxide comprising ethylene oxide, wherein theethylene oxide accounts for over half of the alkylene oxide, and a fattyacid comprising 8 to 24 carbon atoms; and (iii) a fatty acid amidecomprising a hydroxyl group.
 2. The polylactic acid resin compositionaccording to claim 1, wherein the reaction product (ii) comprises 30 to95 wt % of an oxyethylene group.
 3. The polylactic acid resincomposition according to claim 1, wherein the reaction product (ii)comprises a hydroxyl group derived from the alkylene oxide.
 4. Thepolylactic acid resin composition according to claim 1, wherein thereaction product (ii) comprises 0.5 or more and less than 2.5 estergroups on average in a molecule thereof.
 5. The polylactic acid resincomposition according to claim 1, wherein the fatty acid amide (iii)comprises a bisamide compound obtained by causing a fatty acidcomprising 8 to 24 carbon atoms and comprising a hydroxyl group, and acompound comprising two amino groups to react with each other.
 6. Thepolylactic acid resin composition according to claim 1, wherein acontent of the reaction product (ii) falls within a range of 0.5 to 10parts by weight with respect to 100 parts by weight of the polylacticacid (i).
 7. The polylactic acid resin composition according to claim 1,wherein a content of the fatty acid amide (iii) falls within a range of0.1 to 0.7 part by weight with respect to 100 parts by weight of thepolylactic acid (i).
 8. The polylactic acid resin composition accordingto claim 1, wherein said alkylene oxide is entirely formed of theethylene oxide.
 9. A resin molded article comprising a polylactic acidresin composition consisting essentially of: (i) a polylactic acid; (ii)a reaction product of: at least one selected from the group consistingof sorbitol, mannitol, and dehydration condensates thereof, an alkyleneoxide comprising ethylene oxide, wherein the ethylene oxide accounts forover half of the alkylene oxide, and a fatty acid comprising 8 to 24carbon atoms; and (iii) a fatty acid amide comprising a hydroxyl group.10. The resin molded article according to claim 9, wherein the reactionproduct (ii) comprises 30 to 95 wt % of an oxyethylene group.
 11. Theresin molded article according to claim 9, wherein the reaction product(ii) comprises a hydroxyl group derived from the alkylene oxide.
 12. Theresin molded article according to claim 9, wherein the reaction product(ii) comprises 0.5 or more and less than 2.5 ester groups on average ina molecule thereof.
 13. The resin molded article according to claim 9,wherein the fatty acid amide (iii) comprises a bisamide compoundobtained by causing a fatty acid comprising 8 to 24 carbon atoms andcomprising a hydroxyl group, and a compound comprising two amino groupsto react with each other.
 14. The resin molded article according toclaim 9, wherein a content of the reaction product (ii) falls within arange of 0.5 to 10 parts by weight with respect to 100 parts by weightof the polylactic acid (i).
 15. The resin molded article according toclaim 9, wherein a content of the fatty acid amide (iii) falls within arange of 0.1 to 0.7 part by weight with respect to 100 parts by weightof the polylactic acid (i).
 16. The resin molded article according toclaim 9, wherein said alkylene oxide is entirely formed of the ethyleneoxide.